#define _GNU_SOURCE 1
#include <arpa/inet.h>
#include <assert.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <poll.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

#define BUFFER_SIZE 64

int main(int argc, char *argv[]) {
  const char *ip = argv[1];
  int port = atoi(argv[2]);

  struct sockaddr_in server_address;
  bzero(&server_address, sizeof(server_address));
  server_address.sin_family = AF_INET;
  inet_pton(AF_INET, ip, &server_address.sin_addr);
  server_address.sin_port = htons(port);

  int sockfd = socket(PF_INET, SOCK_STREAM, 0);
  assert(sockfd >= 0);
  if (connect(sockfd, (struct sockaddr *)&server_address,
              sizeof(server_address)) < 0) {
    printf("connection is failed\n");
    close(sockfd);
    return -1;
  }

  struct pollfd fds[2];
  /* 注册文件描述符 0（标准输入）和文件描述符 sockfd 上的可读事件 */
  fds[0].fd = 0;
  fds[0].events = POLLIN;
  fds[0].revents = 0;
  fds[1].fd = sockfd;
  fds[1].events = POLLIN | POLLRDHUP;
  fds[1].revents = 0;

  char read_buf[BUFFER_SIZE];
  int pipefd[2];
  int ret = pipe(pipefd);
  assert(ret != -1);

  while (1) {
    ret = poll(fds, 2, -1);
    if (ret < 0) {
      printf("poll failure.\n");
      break;
    }
    if (fds[1].revents & POLLRDHUP) {
      printf("server close the connection\n");
      break;
    } else if (fds[1].revents & POLLIN) {
      memset(read_buf, 0x0, BUFFER_SIZE);
      recv(fds[1].fd, read_buf, BUFFER_SIZE - 1, 0);
      printf("%s\n", read_buf);
    }

    if (fds[0].revents & POLLIN) {
      /* 使用 splice 将用户输入的数据直接写到 sockfd 上（零拷贝） */
      ret = splice(0, NULL, pipefd[1], NULL, 32768,
                   SPLICE_F_MORE | SPLICE_F_MOVE);
      ret = splice(pipefd[0], NULL, sockfd, NULL, 32768,
                   SPLICE_F_MORE | SPLICE_F_MOVE);
    }
  }

  close(sockfd);
  return 0;
}